Abstract Pentasubstituted cyclopentadienyl complexes of ruthenium R 5 CpRu (CO) 2 Cl (R= Ph, benzyl) form, upon activation with tBuOK, highly active catalysts for racemization of chiral sec-alcohols. In combination with suitable resolving enzymes, such catalyst systems can efficiently be utilized for dynamic kinetic resolution reactions providing chiral alcohols, after hydrolysis of the corresponding acetates, in high yields and high enantiomeric purities. ...